This, but also, it can be an art finding the root of a chord, or a scale, without being told what the chord is. What's the root of a chord that has B-D-G-A from low to high? The answer is G; it's a Gadd9 chord, but because it's inverted, the root of the chord is in the middle of the notes being played. It gets harder with other chords. There are for instance only three unique combinations of notes in any fully-diminished chord; because the interval between each note in the chord is exactly the same, the chord whose root is a minor third higher than another is an inversion of that chord.
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KeithSMar 1 '12 at 17:56